Williams, Azarenka into 4th round at Aussie Open

Serena Williams of the US hits a return to Japan's Ayumi Morita during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 19, 2013. (AP Photo/Andy Wong)
— AP

Serena Williams of the US hits a return to Japan's Ayumi Morita during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 19, 2013. (AP Photo/Andy Wong)
/ AP

Serbia's Novak Djokovic reacts during his third round round match against Radek Stepanek of the Czech Republic at the Australian Open tennis championship in Melbourne, Australia, Friday, Jan. 18, 2013. (AP Photo/Dita Alangkara)— AP

Serbia's Novak Djokovic reacts during his third round round match against Radek Stepanek of the Czech Republic at the Australian Open tennis championship in Melbourne, Australia, Friday, Jan. 18, 2013. (AP Photo/Dita Alangkara)
/ AP

Venus Williams of the US reacts during her third round loss to Russia's Maria Sharapova at the Australian Open tennis championship in Melbourne, Australia, Friday, Jan. 18, 2013. (AP Photo/Dita Alangkara)— AP

Venus Williams of the US reacts during her third round loss to Russia's Maria Sharapova at the Australian Open tennis championship in Melbourne, Australia, Friday, Jan. 18, 2013. (AP Photo/Dita Alangkara)
/ AP

Russia's Maria Sharapova celebrates after defeating Venus Williams of the US in their third round match at the Australian Open tennis championship in Melbourne, Australia, Friday, Jan. 18, 2013. (AP Photo/Dita Alangkara)— AP

Russia's Maria Sharapova celebrates after defeating Venus Williams of the US in their third round match at the Australian Open tennis championship in Melbourne, Australia, Friday, Jan. 18, 2013. (AP Photo/Dita Alangkara)
/ AP

Russia's Maria Sharapova celebrates after defeating Venus Williams of the US in their third round match at the Australian Open tennis championship in Melbourne, Australia, Friday, Jan. 18, 2013. (AP Photo/Dita Alangkara)— AP

Russia's Maria Sharapova celebrates after defeating Venus Williams of the US in their third round match at the Australian Open tennis championship in Melbourne, Australia, Friday, Jan. 18, 2013. (AP Photo/Dita Alangkara)
/ AP

Britain's Andy Murray serves to Lithuania's Ricardas Berankis during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 19, 2013. (AP Photo/Andy Wong)— AP

Jamie Hampton of the US gets treatment during her third round match against Victoria Azarenka of Belarus at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 19, 2013. (AP Photo/Andy Wong)— AP

Jamie Hampton of the US gets treatment during her third round match against Victoria Azarenka of Belarus at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 19, 2013. (AP Photo/Andy Wong)
/ AP

Serena Williams of the US serves to Japan's Ayumi Morita during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 19, 2013. (AP Photo/Andy Wong)— AP

Serena Williams of the US serves to Japan's Ayumi Morita during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 19, 2013. (AP Photo/Andy Wong)
/ AP

Victoria Azarenka of Belarus wipes the sweat from her face during her third round match against Jamie Hampton of the US at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 19, 2013. (AP Photo/Andy Wong)— AP

Victoria Azarenka of Belarus wipes the sweat from her face during her third round match against Jamie Hampton of the US at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 19, 2013. (AP Photo/Andy Wong)
/ AP

MELBOURNE, Australia 
Serena Williams and Victoria Azarenka advanced in contrasting styles Saturday to the fourth round at the Australian Open.

Williams, the tournament favorite aiming for a third consecutive major title, recovered from a break down in the second set to win six straight games and finish off a 6-1, 6-3 win over Japan's Ayumi Morita in 66 minutes.

Azarenka, the top-ranked defending champion, struggled to hold off injured American Jamie Hampton 6-4, 4-6, 6-2 - and she didn't help herself with six double-faults.

At least she survived.

Juan Martin del Potro, the 2009 U.S. Open champion, lost a marathon match 6-3, 6-3, 6-7 (3), 3-6, 6-3 to Jeremy Chardy of France, leaving only three major winners in the men's draw.

Andy Murray, who joined the ranks of the Grand Slam winners at last year's U.S. Open, advanced with a gritty 6-3, 6-4, 7-5 win over Lithuanian qualifier Ricardas Berankis.

"I feel so much emotion. Five sets, to be here in a Grand Slam. It's the most beautiful match of my career," Chardy said. "It's a great moment for me, everyone dreams of this."

Second-ranked Roger Federer, who has four Australian titles among his record 17 majors, was playing Bernard Tomic later Saturday after No. 1 Novak Djokovic took another step toward his third consecutive Australian title with a third-round win Friday.

After taking del Potro out of the top section of the draw, Chardy will next face No. 21 Andreas Seppi of Italy, who ousted No. 12 Marin Cilic with a 6-7 (2), 6-3, 2-6, 6-4, 6-2 victory.

A pair of Frenchmen advanced and will meet in the fourth round, with No. 7 Jo-Wilfried Tsonga beating Slovenia's Blaz Kavcic 6-2, 6-1, 6-4 to set up a meeting with No. 9 Richard Gasquet, who fended off Croatia's Ivan Dodig 4-6, 6-3, 7-6 (2), 6-0.

Williams surprised herself with another serve at 128 mph in an afternoon match on Rod Laver Arena, matching a career best that she hit earlier in the tournament.

"I tried to hit it really hard. I hit 207 (kph) the other day and I thought it was luck," she said. "But I did it again and I was like, `Whew! I'm going to try to go for 210.' We'll see."

Azarenka appeared frustrated at times, but overcame an early break and fended off triple break point in the seventh game of the deciding set before clinching the match in 2 hours, 9 minutes.

Hampton needed a medical timeout for a lower back problem before she served out the second set. She winced in pain and was frequently on the verge of tears throughout the third set, but still managed 41 winners to keep the Belarusian under pressure.

"She played incredible, went for every single shot. I felt it was touching every single line," Azarenka said. "She took a medical timeout but she rips winners all over the place and I was like, `Can I have a back problem?' I'm feeling great, but I'm missing every shot."